96 percent of the global demand for seaweed is met by aquaculture; the rest is wild harvested.

Most seaweed produced is for human consumption, with some used for animal and fish feed and for fertilizer. Over the past decade, there has also been increasing demand for seaweed for biotechnological and medical applications.

Most seaweed is cultivated in China (which produced 12.8 million tons in 2014), Indonesia, Japan, the Republic of Korea, and the Philippines. Seaweed farms are also found today in Northern Europe, Canada, South America, and East Africa.

One of the main commercial species, the red seaweed Kappaphycus, is grown for its carrageenan, which is used as a thickening agent in foods and pharmaceuticals.

Seaweed farming is one of the most eco-friendly types of aquaculture. It doesn’t require additional feed (like fish farming does), for example. In fact, seaweed farms help the environment by protecting the underlying seabed and by removing excess nutrients in bodies of water that otherwise would cause algae overgrowth. Some seaweed is cultivated alongside abalone and sea cucumber, in an integrated system whereby “the wastes of one resource user becomes a resource (fertilizer or food) for others,” according to the report.

But like all aquaculture, seaweed farming is susceptible to disease, introduction of pests, interbreeding of “escapees” with native species, and other unforeseen ecological and socioeconomic problems, highlighting the need for producers to implement and improve protective measures.